Alias-Filters - Yes or No ?

An alias filter is a soft-edged glass in front of the sensor of digital cameras. It is required to remove frequencies higher than half the sensor pixel density (Nyquist limit), before sampling (digitization). The alias filter consists of a light unsharp mask (Blur) and acts as an optical low-pass. For some years individual manufacturers omit the alias filter in their cameras and praise this as improvement of sharpness and resolution. But is this really?

The Nyquist Limit

It can be read in journals that tests of a camera have passed the Nyquist limit with high resolution (as seen in the German magazine ColorFoto 4/2013 on page 31). This pops up the inevitable question, how sharp this ominous border really is. Obviously this limit is no longer relevant for modern cameras when it can be passed at a high level. Was this Nyquist a stupid guy or didn't he simply knew better? Probably soon another, more clever person will find a much higher "Meier-border". And in some years there is perhaps no longer any border, because technology has progressed.

The iPhone camera

Crop factor and optical equivalence - How to take similar images with different cameras

Modern cameras come in many different sensor sizes. It is of great interest for ambitious photographers what settings should be used to create images that are comparable to other cameras with different sensor sizes. It is also interesting to compare very small sensors, for example of smartphone cameras, to full-frame sensors in order to better understand their photographic potential.

Crop factor and optical equivalence - How to take similar images with different cameras

Modern cameras come in many different sensor sizes. It is of great interest for ambitious photographers what settings should be used to create images that are comparable to other cameras with different sensor sizes. It is also interesting to compare very small sensors, for example of smartphone cameras, to full-frame sensors in order to better understand their photographic potential.

The benefits of large sensors

What are the true, technical benefits of camera systems with large sensors (for example full frame or medium format) over camera systems with smaller sensors (for example APS-C)? This blog entry has the answers.